Design of ACI-type punching shear reinforcement to Eurocode 2

This paper describes a series of tests that were carried out at Imperial College London to determine the efficiency of stirrups when used as ACI-type punching shear reinforcement at internal columns. Six 3 m square slabs were tested with various arrangements of punching shear reinforcement. The variables considered in the tests included the area of shear reinforcement and the extension of the stirrups from the column face. The measured shear strengths were compared with the shear strengths predicted with Eurocode 2 and ACI 318. The design method in Eurocode 2 is shown to be overly conservative for ACI-type punching shear reinforcement and a modification is proposed. The paper describes a series of three-dimensional non-linear finite-element analyses which were carried out to gain a better appreciation of the parameters influencing the efficiency of ACI-type shear reinforcement and to assist in the validation of the proposed design method. The non-linear finite-element analysis is shown to give good predictions of the measured shear strengths of the tested slabs.